Recherche Images Maps Play YouTube Actualités Gmail Drive Plus »
Connexion
Les utilisateurs de lecteurs d'écran peuvent cliquer sur ce lien pour activer le mode d'accessibilité. Celui-ci propose les mêmes fonctionnalités principales, mais il est optimisé pour votre lecteur d'écran.

Brevets

  1. Recherche avancée dans les brevets
Numéro de publicationUS7115126 B2
Type de publicationOctroi
Numéro de demandeUS 10/123,849
Date de publication3 oct. 2006
Date de dépôt15 avr. 2002
Date de priorité23 oct. 1998
État de paiement des fraisCaduc
Autre référence de publicationDE69925621D1, DE69925621T2, EP1123135A2, EP1123135B1, US6245062, US6312427, US6364876, US6383182, US7052491, US7387627, US20020128642, US20020193786, US20030036754, US20060015094, WO2000024463A2, WO2000024463A3
Numéro de publication10123849, 123849, US 7115126 B2, US 7115126B2, US-B2-7115126, US7115126 B2, US7115126B2
InventeursDany Berube, Robert E. Woodard, Theodore C. Ormsby
Cessionnaire d'origineAfx Inc.
Exporter la citationBiBTeX, EndNote, RefMan
Liens externes: USPTO, Cession USPTO, Espacenet
Directional microwave ablation instrument with off-set energy delivery portion
US 7115126 B2
Résumé
A directional ablation instrument for ablation of a targeted tissue. The instrument includes a transmission line having a proximal portion suitable for connection to an electromagnetic energy source, and an elongated antenna device having a longitudinal axis and an end coupled to the transmission line. The antenna is adapted to generate an electric field sufficiently strong to cause tissue ablation of the targeted tissue. An elongated support assembly includes a central axis, and an ablation surface extending longitudinally along an exterior surface portion of the support assembly. The support assembly is configured to receive the antenna device in the ablation surface such that the longitudinal axis of the antenna device is off-set from the support assembly central axis. Further, the antenna device is oriented toward the surface portion for positioning of the antenna device substantially adjacent to or in contact with the targeted tissue during operable use.
Images(4)
Previous page
Next page
Revendications(5)
1. A directional ablation instrument for ablation of a targeted tissue, comprising:
a transmission line having a distal end and a proximal portion suitable for connection to an electromagnetic energy source;
an elongated antenna having an end coupled to the distal end of the transmission line, the elongated antenna adapted to generate an electric field sufficiently strong to cause tissue ablation of the targeted tissue; and
an elongated antenna assembly including a conductive structure disposed about the antenna and having a window therein for directing a majority of the electric field through the window in substantially one radial direction with respect to a central axis of the elongated antenna assembly, the elongated antenna being fixedly located within the elongated antenna assembly with a central axis of the elongated antenna off-set from the central axis of the elongated antenna assembly toward the window therein.
2. The instrument of claim 1, wherein the elongated assembly includes a layer of insulation fixedly disposed over the conductive structure and is adapted to conform to at least a portion of the targeted tissue during use.
3. A directional ablation instrument for ablating of a targeted tissue, comprising:
at least one ablating element including a RF antenna adapted to emit electromagnetic ablating energy for ablating the targeted tissue in response to applied radio frequency electromagnetic energy; and
an elongated assembly having a central axis and defining a conductive structure about the antenna of the ablation instrument and including a non-conductive window in the conductive structure for directing a majority of the RF ablating energy throught the window in substantially one radial direction with respect to the central axis, the at least one ablating element being fixedly located within the elongated assembly with, the central axis of the at least one ablating element offset toward the window of the elongated assembly.
4. A directional ablation instrument for ablating target issue, comprising:
a flexible elongated antenna adapted to generate an electric field sufficiently strong to cause ablation of targeted tissue in response to electromagnetic energy supplied thereto; and
a flexible elongated antenna assembly having an elongated transmission aperture disposed in alignment with a central axis of the assembly, the elongated antenna being fixedly disposed contiguous the transmission aperture and offset from the central axis of the elongated antenna assembly for directing a majority of the electric field in substantially the radial direction with respect to the central axis and through the transmission aperture.
5. A directional ablation instrument for ablating targeted tissue, comprising:
an ablating element including an antenna adapted to emit electromagnetic ablation energy for ablating the targeted tissue; and
an electrically conductive elongated assembly fixed disposed about the antenna and having a central axis and forming an outer surface of the ablation instrument, the elongated assembly including an electromagnetic energy transmissin aperture through the outer surface with the antenna disposed contiguous the transmission aperture and offset from the central axis of the elongated assembly for directing a majority of the ablation energy in substantially one radial direction with respect to the central axis and through the transmission aperture.
Description
RELATED APPLICATION

This application is a continuation of patent application Ser. No. 09/651,560, filed on Aug. 30, 2000, and entitled DIRECTIONAL MICROWAVE ABLATION INSTRUMENT WITH OFF-SET ENERGY DELIVERY PORTION now issued as U.S. Pat. No. 6,383,182, which is a continuation of patent application Ser. No. 09/178,066, filed Oct. 23, 1998, and entitled “DIRECTIONAL REFLECTOR SHIELD ASSEMBLY FOR A MICROWAVE ABLATION INSTRUMENT now issued as U.S. Pat. No. 6,245,062.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates, generally, to ablation instrument systems that use electromagnetic energy in the microwave frequencies to ablate internal bodily tissues, and, more particularly, to antenna arrangements and instrument construction techniques that direct the microwave energy in selected directions that are relatively closely contained along the antenna.

2. Description of the Prior Art

It is well documented that atrial fibrillation, either alone or as a consequence of other cardiac disease, continues to persist as the most common cardiac arrhythmia. According to recent estimates, more than one million people in the U.S. suffer from this common arrhythmia, roughly 0.15% to 1.0% of the population. Moreover, the prevalence of this cardiac disease increases with age, affecting nearly 8% to 17% of those over 60 years of age.

Although atrial fibrillation may occur alone, this arrhythmia often associates with numerous cardiovascular conditions, including congestive heart failure, hypertensive cardiovascular disease, myocardial infarcation, rheumatic heart disease, and stroke. Regardless, three separate detrimental sequelae result: (1) a change in the ventricular response, including the onset of an irregular ventricular rhythm and an increase in ventricular rate; (2) detrimental hemodynamic consequences resulting from loss of atroventricular synchrony, decreased ventricular filling time, and possible atrioventricular valve regurgitation; and (3) an increased likelihood of sustaining a thromboembolic event because of loss of effective contraction and atrial stasis of blood in the left atrium.

Atrial arrhythmia may be treated using several methods. Pharmacological treatment of atrial fibrillation, for example, is initially the preferred approach, first to maintain normal sinus rhythm, or secondly to decrease the ventricular response rate. While these medications may reduce the risk of thrombus collecting in the atrial appendages if the atrial fibrillation can be converted to sinus rhythm, this form of treatment is not always effective. Patients with continued atrial fibrillation and only ventricular rate control continue to suffer from irregular heartbeats and from the effects of impaired hemodynamics due to the lack of normal sequential atrioventricular contractions, as well as continue to face a significant risk of thromboembolism.

Other forms of treatment include chemical cardioversion to normal sinus rhythm, electrical cardioversion, and RF catheter ablation of selected areas determined by mapping. In the more recent past, other surgical procedures have been developed for atrial fibrillation, including left atrial isolation, transvenous catheter or cryosurgical ablation of His bundle, and the Corridor procedure, which have effectively eliminated irregular ventricular rhythm. However, these procedures have for the most part failed to restore normal cardiac hemodynamics, or alleviate the patient's vulnerability to thromboembolism because the atria are allowed to continue to fibrillate. Accordingly, a more effective surgical treatment was required to cure medically refractory atrial fibrillation of the heart.

On the basis of electrophysiologic mapping of the atria and identification of macroreentrant circuits, a surgical approach was developed which effectively creates an electrical maze in the atrium (i.e., the MAZE procedure) and precludes the ability of the atria to fibrillate. Briefly, in the procedure commonly referred to as the MAZE III procedure, strategic atrial incisions are performed to prevent atrial reentry and allow sinus impulses to activate the entire atrial myocardium, thereby preserving atrial transport function postoperatively. Since atrial fibrillation is characterized by the presence of multiple macroreentrant circuits that are fleeting in nature and can occur anywhere in the atria, it is prudent to interrupt all of the potential pathways for atrial macroreentrant circuits. These circuits, incidentally, have been identified by intraoperative mapping both experimentally and clinically in patients.

Generally, this procedure includes the excision of both atrial appendages, and the electrical isolation of the pulmonary veins. Further, strategically placed atrial incisions not only interrupt the conduction routes of the common reentrant circuits, but they also direct the sinus impulse from the sinoatrial node to the atrioventricular node along a specified route. In essence, the entire atrial myocardium, with the exception of the atrial appendages and the pulmonary veins, is electrically activated by providing for multiple blind alleys off the main conduction route between the sinoatrial node to the atrioventricular node. Atrial transport function is thus preserved postoperatively as generally set forth in the series of articles: Cox, Schuessler, Boineau, Canavan, Cain, Lindsay, Stone, Smith, Corr, Change, and D'Agostino, Jr., The Surgical Treatment Atrial Fibrillation (pts. 1-4), 101 THORAC CARDIOVASC SURG., 402-426, 569-592 (1991).

While this MAZE III procedure has proven effective in ablating medically refractory atrial fibrillation and associated detrimental sequelae, this operational procedure is traumatic to the patient since substantial incisions are introduced into the interior chambers of the heart. Consequently, other techniques have thus been developed to interrupt and redirect the conduction routes without requiring substantial atrial incisions. One such technique is strategic ablation of the atrial tissues through ablation catheters.

Most approved ablation catheter systems now utilize radio frequency (RF) energy as the ablating energy source. Accordingly, a variety of RF based catheters and power supplies are currently available to electrophysiologists. However, radio frequency energy has several limitations including the rapid dissipation of energy in surface tissues resulting in shallow “burns” and failure to access deeper arrhythmic tissues. Another limitation of RF ablation catheters is the risk of clot formation on the energy emitting electrodes. Such clots have an associated danger of causing potentially lethal strokes in the event that a clot is dislodged from the catheter.

As such, catheters which utilize electromagnetic energy in the microwave frequency range as the ablation energy source are currently being developed. Microwave frequency energy has long been recognized as an effective energy source for heating biological tissues and has seen use in such hyperthermia applications as cancer treatment and preheating of blood prior to infusions. Accordingly, in view of the drawbacks of the traditional catheter ablation techniques, there has recently been a great deal of interest in using microwave energy as an ablation energy source. The advantage of microwave energy is that it is much easier to control and safer than direct current applications and it is capable of generating substantially larger lesions than RF catheters, which greatly simplifies the actual ablation procedures. Typical of such microwave ablation systems are described in the U.S. Pat. No. 4,641,649 to Walinsky; U.S. Pat. No. 5,246,438 to Langberg; U.S. Pat. No. 5,405,346 to Grundy, et al.; and U.S. Pat. No. 5,314,466 to Stern, et al, each of which is incorporated herein by reference.

Most of the existing microwave ablation catheters contemplate the use of longitudinally extending helical antenna coils that direct the electromagnetic energy in a radial direction that is generally perpendicular to the longitudinal axis of the catheter although the fields created are not well constrained to the antenna itself. Although such catheter designs work well for a number of applications, such radial output, while controlled, is inappropriate for use in MAZE III procedures for example which require very strategically positioned and formed lesions. Thus, it would be desirable to provide microwave ablation catheter designs that are capable of effectively transmitting electromagnetic energy that more closely approximates the length of the antenna, and in a specific direction, such as generally perpendicular to the longitudinal axis of the catheter but constrained to a selected radial region of the antenna.

SUMMARY OF THE INVENTION

To achieve the foregoing and other objects and in accordance with the purpose of the present invention, a variety of improved ablation instruments and particularly microwave ablation instruments are disclosed. In some embodiments, a directional reflective shield assembly is provided for a microwave ablation instrument having an antenna coupled to a transmission line. The antenna is formed to generate an electric field sufficiently strong to cause tissue ablation. The shield includes a cradle device disposed about the antenna in a manner substantially shielding a surrounding area of the antenna from the electric field radially generated therefrom. The cradle device further provides a window portion communicating with the antenna which is strategically located relative the antenna to direct a majority of the field generally in a predetermined direction.

In one embodiment, an insert device is disposed in a cavity of the cradle. The insert device provides a recess formed and dimensioned for receipt of the antenna therein in a manner substantially isolating the antenna from direct contact with the cradle device. The insert device further includes a directional port extending into the recess and aligned to communicate with the window portion of the cradle device to direct the majority of the field generally in the predetermined direction.

Another embodiment includes an insulator in conductive contact with the cradle device to transfer heat therefrom. The insulator is preferably disposed about the cradle member, and includes a longitudinally extending bore formed and dimensioned for sliding receipt of the cradle device therein. A directional window extends into the bore and is aligned to communicate with the window portion of the cradle device and the directional port of the insert device to direct the majority of the field generally in the predetermined direction.

In still another embodiment, a microwave ablation instrument includes a transmission line having a proximal portion suitable for connection to an electromagnetic energy source, and an antenna coupled to the transmission line for radially generating an electric field sufficiently strong to cause tissue ablation. A shield assembly is coupled to the antenna to substantially shield a surrounding area of the antenna from the electric field radially generated therefrom while permitting a majority of the field to be directed generally in a predetermined direction.

In yet another embodiment, a microwave ablation instrument includes a bendable, malleable tubular shaft having a proximal portion and a distal portion, and a transmission line disposed within the tubular shaft. The transmission line includes a proximal portion suitable for connection to an electromagnetic energy source. An antenna is supported by the distal portion of the tubular shaft, and is coupled to the transmission line for radially generating an electric field sufficiently strong to cause tissue ablation. A microwave absorbent is disposed peripherally around the proximal portion of the tubular shaft to substantially absorb residual microwave radiation transmitted by the proximal portion thereof.

In one embodiment, a handle is provided which is mounted to the proximal portion of the tubular shaft. The handle includes an interior wall defining a cavity portion formed and dimensioned for termination of the tubular shaft proximal portion terminates therein. A material containing a silicon based microwave absorbent is disposed about the proximal portion and the transmission line in the cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

The assembly of the present invention has other objects and features of advantage which will be more readily apparent from the following description of the best mode of carrying out the invention and the appended claims, when taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a diagrammatic top plan view, in cross-section, of a microwave ablation instrument system with a directional reflective shield assembly constructed in accordance with one embodiment of the present invention.

FIG. 2 is an enlarged, fragmentary, top perspective view of the shield assembly of FIG. 1 mounted to an antenna assembly of the ablation instrument system.

FIG. 3 is a side elevation view, in cross-section, of the shield assembly of FIG. 2.

FIG. 4 is a front elevation view of the shield assembly taken substantially along the plane of the line 4-4 in FIG. 3.

FIG. 5 is an exploded, side elevation view, in cross-section, of the shield assembly of FIG. 2, illustrating sliding receipt of an insert device in a cradle device of the shield assembly.

FIG. 6 is a fragmentary, side elevation view, in cross-section, of a handle of the ablation instrument system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

While the present invention will be described with reference to a few specific embodiments, the description is illustrative of the invention and is not to be construed as limiting the invention. Various modifications to the present invention can be made to the preferred embodiments by those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims. It will be noted here that for a better understanding, like components are designated by like reference numerals throughout the various FIGURES.

Turning now to FIGS. 1 and 2, a microwave ablation instrument, generally designated 20, is provided which includes a transmission line 21 having a proximal portion 22 suitable for connection to an electromagnetic energy source (not shown), and an antenna 23 coupled to the transmission line 21 for radially generating an electric field sufficiently strong to cause tissue ablation. A shield assembly, generally designated 25, is coupled to the antenna 23 to substantially shield a peripheral area immediately surrounding the antenna from the electric field radially generated therefrom while permitting a majority of the field to be directed generally in a predetermined direction.

More specifically, a directional reflective shield assembly 25 is provided for a microwave ablation instrument including a cradle device 26 disposed about the antenna 23 in a manner substantially shielding a surrounding area of the antenna from the electric field radially generated therefrom. The cradle device 26 further provides a window portion 27 communicating with the antenna 23 which is strategically located relative the antenna to direct a majority of the field generally in a predetermined direction.

Accordingly, the shield assembly of the present invention enables predetermined directional transmission of the electric field regardless of the radial transmission pattern of the antenna. Tissue ablation can thus be more strategically controlled, directed and performed without concern for undesirable ablation of other adjacent tissues which may otherwise be within the electromagnetic ablation range radially emanating from the antenna. In other words, any other tissues surrounding the peripheral sides of the antenna which are out of line of the window portion of the cradle will not be subjected to the directed electric field and thus not be ablated. This ablation instrument assembly is particularly suitable for ablation procedures requiring accurate tissue ablations such as those required in the MAZE III procedure above-mentioned.

It will be appreciated that the phrase “peripheral area immediately surrounding the antenna” is defined as the immediate radial transmission pattern of the antenna which is within the electromagnetic ablation range thereof when the shield assembly is absent.

Transmission line 21, which is supported within a tubular shaft 31, is typically coaxial, and coupled to a power supply (not shown) which is external to instrument 20. As best illustrated in FIGS. 2 and 3, the microwave ablation instrument 20 generally includes an antenna 23 with a proximal end 28 and a distal end 30. The proximal end 28 of antenna 23 is grounded to an outer conductor (not shown) of transmission line 21. The distal end 30 of antenna 23 is attached to center conductor 32 of transmission line 21. Typically, antenna 23 is helical or in the form of a coil, i.e. an antenna coil, which is made from any suitable material, such as spring steel, beryllium copper, or silver-plated copper. However, the antenna may be any other configuration, such as a monopole, which radiates a cylindrical pattern consistent with the length thereof. The connection between the antenna 23 and center conductor 32 may be made in any suitable manner such as soldering, brazing, ultrasonic welding or adhesive bonding. In other embodiments, the antenna 23 can be wound from the center conductor of the transmission line itself. This is more difficult from a manufacturing standpoint but has the advantage of forming a more rugged connection between the antenna and center conductor.

The outer diameter of antenna coil 23 will vary to some extent based on the particular application of the instrument. By way of example, a instrument suitable for use in an atrial fibrillation application may have typical coil outer diameters in the range of approximately 0.07 to 0.10 inches. More preferably, the outer diameter of antenna coil 23 may be in the range of approximately 0.08 to 0.09 inches.

The actual number of turns of the antenna coil may vary a great deal in accordance with the needs of a particular system. Some of the factors that will dictate the number of turns used include the coil diameter and pitch, the desired length of the lesion, the antenna configuration, the instrument diameter, the frequency of the electromagnetic energy, the desired field strength and the match within the tissue. Moreover, since these coiled antennas are preferably filled or cast with a silicone insulator to insulate each coil from one another and from the center conductor, the pitch of the coils can be smaller and the number of turns increased. In MAZE III applications, for example, the antenna is comprised of about thirty-seven (37) turns, and has a length in the range of approximately 19.8 mm to 20.0 mm. The antenna is typically spaced at least 0.5 mm, as for example in the range of approximately 0.5 to 2.0 mm, from the distal end of the transmission line shield (not shown) and at least approximately 0.5 mm, as for example in the range of approximately 0.5 to 1.0 mm from the distal end of the transmission line dielectric 33.

To substantially reduce or eliminate electromagnetic radiance of the distal end of the transmission line 21, the antenna is fed at its resonance frequency to better define the electromagnetic field along the coil. The antenna is preferably tuned by adjusting the length and the number of turns of the coil so that the resonance frequency of the radiative structure is in the range of about 2.45 GHz, for example. Consequently, the energy delivery efficiency of the antenna is increased, while the reflected microwave power is decreased which in turn reduces the operating temperature of the transmission line. Moreover, the radiated electromagnetic field is substantially constrained from the proximal end to the distal end of the antenna. Thus, when a longitudinally extending coil is used, the field extends substantially radially perpendicularly to the antenna and is fairly well constrained to the length of the antenna itself regardless of the power used. This arrangement serves to provide better control during ablation. Instruments having specified ablation characteristics can be fabricated by building instruments with different length antennas.

Briefly, the power supply (not shown) includes a microwave generator which may take any conventional form. When using microwave energy for tissue ablation, the optimal frequencies are generally in the neighborhood of the optimal frequency for heating water. By way of example, frequencies in the range of approximately 800 MHz to 6 GHz work well. Currently, the frequencies that are approved by the U.S. Food and Drug Administration for experimental clinical work are 915 MHz and 2.45 GHz. Therefore, a power supply having the capacity to generate microwave energy at frequencies in the neighborhood of 2.45 GHz may be chosen. At the time of this writing, solid state microwave generators in the 1-3 GHz range are very expensive. Therefore, a conventional magnetron of the type commonly used in microwave ovens is utilized as the generator. It should be appreciated, however, that any other suitable microwave power source could be substituted in its place, and that the explained concepts may be applied at other frequencies like about 434 MHz, 915 MHz or 5.8 GHz (ISM band).

Referring back to FIGS. 2 and 3, the shield assembly of the present invention will be described in detail. In accordance with the present invention, cradle device 26 defines a window portion 27 strategically sized and located to direct a majority of the electromagnetic field generally in a predetermined direction. Cradle device 26 is preferably tubular or cylindrical-shell shaped having an interior wall 35 defining a cavity 36 extending therethrough which is formed for receipt of the antenna 23 therein. While the cradle device is shown and described as substantially cylindrical-shaped along the longitudinal and cross-section dimensions, it will be appreciated that a plurality of forms may be provided to accommodate different antenna shapes or to conform to other external factors necessary to complete a surgical procedure. For example, by longitudinally curving the antenna, either through manual bending or through manufacture, a curvilinear ablative pattern may be achieved. Such a configuration, by way of example, may be necessary when ablating tissue around the pulmonary veins in the MAZE III procedure

Cradle device 26 is preferably thin walled to minimize weight addition to the shield assembly, while being sufficiently thick to achieve the appropriate microwave shielding as well as provide the proper mechanical rigidity to the antenna area. In the preferred embodiment, cradle device 26 is composed of a conductive, metallic material which inherently functions as a reflector. The walls of the cradle device, therefore, are substantially impenetrable to the passage of microwaves emanating from the antenna. Moreover, a percentage of microwaves may be reflected them back into the cavity 36, and subsequently remitted out of window portion 27. One particularly suitable material is stainless steel, for example, having a thickness in the range of about 0.010 inches to about 0.025 inches, and more preferably about 0.015 inches.

As mentioned, an elongated helical microwave antenna normally emits an electromagnetic field substantially radially perpendicular to the antenna length which is fairly well constrained to the length of the coil regardless of the power used. Accordingly, the proximal and distal ends of the cradle may not require shielding by the cradle device in the same manner as that required radially perpendicular to the longitudinal axis of the antenna.

As best viewed in FIGS. 4 and 5, window portion 27 preferably radially extends through one side of the cradle and into the cavity 36, and further extends longitudinally along cradle in a direction substantially parallel to the longitudinal axis thereof. The length of the ablative radiation is therefore generally constrained to the length of the coil, and may be adjusted by either adjusting the length of the antenna (a helical antenna for example), or by adjusting the longitudinal length of the window portion 27. To maximize efficiency, however, the length of the window portion 27 is generally a little longer than the longitudinal length of the antenna 23, by about 1-2 mm on each side. This allows reflections out of the window portion. It will be appreciated, however, that the window portion may be collectively defined by a plurality of sections (not shown), or that the cradle device may include more than one strategically positioned window portion.

For a tubular cradle device 26, FIG. 4 illustrates that the circumferential opening of the window portion 27 may extend circumferentially from about 45° to about 180°, and most preferably extend circumferentially about 160°. A substantial portion of the backside of the antenna, therefore, is shielded from ablative exposure of the microwaves radially generated by the antenna in directions substantially perpendicular to the longitudinal axis 37 thereof. The circumferential dimension of window portion 27, hence, may vary according to the breadth of the desired ablative exposure without departing from the true spirit and nature of the present invention.

Accordingly, the predetermined direction of the ablative electromagnetic field radially generated from the antenna may be substantially controlled by the circumferential opening dimension, the length and the shape of the cradle window portion 27. Manipulating the positioning of window portion 27 in the desired direction, thus, controls the direction of the tissue ablation without subjecting the remaining peripheral area immediately surrounding the antenna to the ablative electromagnetic field.

Briefly, ablation instrument 20 includes a handle 38 coupled to the antenna and the cradle device 26 through an elongated tubular shaft 31. By manually manipulating the handle, the cradle window portion 27 may be oriented and positioned to perform the desired ablation. The shaft is preferably provided by a metallic hypotube which is mounted to the metallic cradle device through brazing paste, welding or the like.

Moreover, the shaft 31 is preferably bendable and malleable in nature to enable shape reconfiguration to position the antenna and the cradle device at a desired orientation relative the handle. This enables the surgeon to appropriately angle the window portion toward the targeted region for tissue ablation. It will be appreciated, however, that the material of the shaft is further sufficiently rigid so that the shaft is not easily deformed during operative use. Such materials, for example, includes stainless steel or aluminum having diameters ranging from about 0.090 inches to about 0.200 inches with wall thickness ranging from about 0.050 inches to about 0.025 inches. Most preferably, the shaft is 304 stainless steel having an outer diameter of about 0.120 inches and a wall thickness of about 0.013 inches.

The resonance frequency of the antenna is preferably tuned assuming contact between the targeted tissue and the longitudinal dimension of the antenna 23 exposed by the window portion 27. Hence, should a portion of, or substantially all of, the exposed region of the antenna not be in contact with the targeted tissue during ablation, the resonance frequency will be adversely changed and the antenna will be untuned. As a result, the portion of the antenna not in contact with the targeted tissue will radiate the electromagnetic radiation into the surrounding air. The efficiency of the energy delivery into the tissue will consequently decrease which in turn causes the penetration depth of the lesion to decrease.

Thus, tissue contact with the antenna is best achieved placing and orienting the antenna longitudinally adjacent and into the cradle window portion 27, as viewed in FIGS. 3 and 4. The longitudinal axis 37 of the antenna is thus off-set from, but parallel to, the longitudinal axis 40 of cradle device 26 in a direction toward the window portion. In this regard, the antenna may generally be positioned closer to the area designated for tissue ablation. Moreover, by positioning the antenna actively in the window portion 27 of the cradle device, the transmissive power of the antenna may be effected substantially along the full circumferential opening of the window portion 27.

This arrangement of positioning the antenna actively in the cradle window portion 27 is partially achieved by mounting a distal portion of shaft 31 in alignment with the window portion, and to an interior wall 35 of cradle device 26. As shown in FIG. 3, the distal end of the shaft 31 extends through a proximal opening 41 into cavity 36 of the cradle device 26 which initially positions the longitudinal axis of the shaft and that of the cradle device substantially parallel one another. It will be appreciated, however, that these axes need not be parallel.

To maintain the electromagnetic field characteristics of the antenna during operative use, it is imperative to stabilize the position of antenna 23 relative the cradle device 26. Relative position changes or antenna deformation may alter the resonant frequency of the antenna, which in turn, changes the field characteristics of the antenna. Accordingly, to stabilize the antenna 23 relative the cradle device 26, the shield assembly 25 further includes an insert device, generally designated 42, disposed in cradle device cavity 36 between the cradle device and the antenna.

Insert device 42 includes a longitudinally extending recess 43 formed and dimensioned for press-fit receipt of the antenna therein. In accordance with the present invention, the recess 43 is preferably cylindrical shaped and extends substantially longitudinally along a surface of the insert device. This configuration positions, stabilizes and retains the helical antenna 23 actively in the window portion 27 to maximize exposure of the targeted tissue to the microwaves generated by antenna. The recess 43 further includes a directional port 45 communicating with the recess 43 which aligns the same with the window portion 27 of the cradle device 26 to direct the majority of the field generally in the predetermined direction. For a curvilinear antenna, it will be understood that the recess may be similarly conformed.

The insert device 42 further performs the function of decreasing the coupling between the antenna 23 and the metallic cradle device 26. Should the antenna be too close to the metallic surface of the cradle device, a strong current may be induced at the surface thereof. This surface current will increase the resistive losses in the metal and the temperature of the cradle device will increase. On the other hand, direct conductive contact or substantially close contact of the antenna with the metallic cradle device will cause the reflective cradle device to become part of the radiative structure, and begin emitting electromagnetic energy in all directions.

Insert device 42 is therefore preferably provided by a good dielectric material which is relatively unaffected by microwave exposure, and thus capable of transmission of the electromagnetic field therethrough. Preferably, this material is provided by a low-loss dielectric material such as TEFLON, silicone, or polyethylene, polyimide, etc.

Insert device 42 is preferably provided by a substantially solid cylindrical structure dimensioned for a sliding interference fit, in the direction of arrow 46 (FIG. 5), through a distal opening 47 of the cradle device cavity 36. Thus, the outer diameter of the insert device is preferably slightly larger than the inner diameter of the cavity 36 defined by cradle interior wall 35. A proximal portion of insert device 42 includes a semicircular alignment tongue 48 formed to cooperate with the distal end of the shaft 31 during sliding receipt of the insert device 42 in the cradle device 26 for alignment thereof. Moreover, a distal portion of the insert device 42 includes an annular shoulder portion 50 formed and dimensioned to contact a distal edge 51 of cradle device 26 upon full insertion of insert device into cavity 36. Collectively, the alignment tongue 48 and the annular shoulder portion 50 cooperate to properly align the recess 43 and the directional port 45, and thus the press-fit antenna 23, in the window portion 27 of the cradle device. Moreover, for reasons to be discussed henceforth, the circumferential dimension of the shoulder portion 50 is conformed substantially similar to that of the cradle device (FIG. 3).

By composing the cradle device 26 of a high conductivity metal, a superior microwave reflector is produced. Thus, when an electromagnetic wave originating from the antenna reaches the cradle device, a surface current is induced. That current will in turn generate a responsive electromagnetic field that will interfere with the incident field in such a way that the total electromagnetic field in the cradle device will be negligible.

While a majority of the electromagnetic energy is reflected by the metallic cradle device 26, since it is not a perfect conductor, a fraction of the incident electromagnetic energy is absorbed by resistive losses therein. Consequently, the cradle device 26 itself may eventually generate heat in an amount detrimental to the surrounding tissue. The shield assembly 25 of the present invention, therefore, preferably includes an insulator 52 disposed about the cradle device 26 to insulate the surrounding tissues from the cradle device. As best viewed in FIGS. 2-4, insulator 52 is disposed peripherally about the cradle device 26 in a manner conductively contacting the outer surface thereof and particularly substantially along its length dimension.

The insulator 52 provides a longitudinally extending bore 53 formed and dimensioned for sliding receipt of the cradle device 26 therein. Preferably, such sliding receipt is performed through an interference fit to insure conductive contact between the insulator and the cradle device. Accordingly, the insulator 52 further performs the function, in part, of a heat sink for the transfer and dissipation of heat into the insulator 52 from the cradle device 26.

Similar to the insert device 42, the insulator 52 defines a directional window 55 extending into the bore 53 from a side wall thereof. This directional window 55 is aligned to communicate with the window portion 27 of the cradle device 26 and the directional port 45 of the insert device 42 so that the cradle device can direct the majority of the field generally in the predetermined direction. Preferably, as viewed in FIG. 4, the directional window 55 of the insulator 52 is circumferentially dimensioned slightly smaller than or substantially equal to the circumferential dimension of the window portion 27 of cradle device 26. This arrangement minimized exposure of the edges defining the window portion 27 to tissues during operation.

To appropriately cool the cradle device during operational use, the insulator 52 must be designed with a sufficient heat transfer capacity to transfer and dissipate the heat continuously generated by the cradle device. One factor determining both the insulatory and heat sink capacity is the material composition. The insulator material, however, preferably has a low loss-tangent and low water absorption so that it is not itself heated by the microwaves. In accordance with the present invention, the insulator is preferably provided by a suitable thermoplastic material such as ABS plastic.

The other primary factor determining the heat sink capacity is the volume of the insulator contacting the cradle device. FIGS. 3 and 4 best illustrate that the insulator 52 is preferably substantially cylindrical-shaped in conformance with the peripheral dimensions of the cradle device 26. The longitudinal axis of bore 53 is off-set from that of the insulator 52 which functions to position the antenna 23 in the aligned windows, and collectively closer to tissues targeted for ablation. Moreover, a backside of the insulator 52 is substantially thicker and more voluminous than the opposed frontside thereof which defines the directional window 55. This configuration provides greater heat sink capacity at the backside of the insulator 52 which conductively contacts a substantial majority of the backside of cradle device 26.

Bore 53 preferably includes a distal opening 58 therein which is formed for sliding receipt of the substantially uniform transverse cross-sectional dimension of the cradle device 26. Sliding support of the insulator 52 longitudinally along the cradle device 26 continues until a back wall 56 of the bore 53 contacts the proximal edge 57 of the cradle device 26. This functions to limit the insertion of the cradle device 26 in the bore 53. At the distal end portion of the insulator 52, the annular shoulder portion 50 of the insert device 42 slideably contacts the interior wall of the bore distal opening 58 to secure the insulator to the cradle device and the insert device. The circumferential dimension of the shoulder portion 50 is preferably dimensioned to provide an interference fit with the shoulder portion. Thus, the outer diameter of the shoulder portion 50 is preferably slightly larger than the inner diameter of the bore 53 of the insulator 52. An adhesive, such as cyanoacrylate, may be applied to further secure the insulator in place.

As shown in FIGS. 2 and 3, once the insulator is properly positioned, the distal end thereof is dimensioned to be positioned substantially flush with the distal end of the insert device 42. Further, the insert device 42 and the insulator 52 cooperate to enclose the distal edge 51 of the cradle device therein.

Referring now to FIG. 6, a handle 38 for the ablation instrument 20 will be described in detail. In the preferred form, the handle 38 is composed of a nonconductive, relatively rigid material, such as ABS plastic. As above-indicated, the handle 38 is provided as a vehicle to manually manipulate the orientation and positioning of the cradle window portion 27 during operational use. This is performed by rigidly attaching the handle to a proximal end portion of the shaft 31.

At a distal portion of the handle 38, a passage 60 extends axially into an interior portion of the handle. The diameter of the passage 60 is preferably substantially equal to the shaft diameter to minimize the tolerance therebetween. An interior wall 61 of the handle portion defines an axially extending cavity 36 which communicates with the distal passage 60. The cavity 36 is preferably of a diameter larger than that of the passage 60, and preferably extends through handle 38 substantially coaxial with the passage 60.

The shaft is positioned in the handle passage 60 such that the shaft proximal end terminates in the cavity 36. To rigidly mount the shaft 31 to the handle 38, an insert screw (not shown) or the like, or an adhesive may be applied in the passage between the shaft 31 and the handle 38.

As shown in FIG. 6, the transmission line 21 extends through the proximal cavity 36 and into the tubular shaft for coupling to the antenna 23. An elastic retraining device 62 may be provided mounted in the cavity 36 at the proximal end of the handle which cooperates with the transmission line 21 to mount the same to the handle.

Due to the conductive nature of the metallic hypotube or tubular shaft 31 and the coaxial arrangement between outer conductor of the coaxial cable and the metallic shaft, a second transmission line is formed between these substantially concentric cylindrical metallic surfaces. Electromagnetic energy emitted by the antenna excites this second transmission line which detrimentally propagates microwave energy between metallic tube and the outer conductor of the coaxial cable. Thus, a part of the microwave energy is propagated back toward the handle.

In accordance with the present invention, handle 38 further includes a microwave absorbent 65 disposed peripherally around the proximal portion of the tubular shaft 31 to substantially absorb microwave radiation transmitted by the proximal end thereof. While the microwave absorbent may be integrally formed in the materials composing the handle, it is preferred that a material 65 containing the microwave absorbent be disposed or wrapped about the juncture 66 between proximal end 63 of the shaft 31 and transmission line 21, as shown in FIG. 6.

In the preferred embodiment, this material wrap 65 is a silicon based microwave absorbent, such as C-RAM KRS-124 from Cuming Microwave Corp. having a thickness of about 0.085 inches. Moreover, this material wrap 65 must be sufficient in length to extend over the juncture 66 between the shaft proximal end 63 and the transmission line 21. Preferably, the wrap extends equidistant from the juncture 66 in each direction by about 0.25 inches to about 0.75 inches. This distance may vary depending upon the anticipated amount of electromagnetic field transmission, the material thickness and the type of microwave absorbent applied.

In accordance with the present invention, to facilitate location of the window portion 27 relative the handle 38 during operative use, a marking device 67 and method are provided. Such location marking is particularly useful during operative use when the antenna and shield assembly cannot be easily viewed.

Preferably, a visual or tactile marking device 67 (FIG. 6) is located along the handle 38 to communicate to the surgeon the location and orientation window portion. This visual marking may be provided by a simple depression mark, painted mark or illuminated mark, or the like easily viewed along the handle. This marking is preferably positioned and aligned in a plane bisecting the window portion 27 and the handle 38. More preferably, as shown in FIG. 6, the marking is positioned on the same side of the handle as the window portion 27. However, it will be understood that the marking may be placed anywhere along the handle 38 as long as the position thereof remains affixed relative the window portion.

Although only a few embodiments of the present inventions have been described in detail, it should be understood that the present inventions may be embodied in many other specific forms without departing from the spirit or scope of the inventions. Particularly, the invention has been described in terms of a microwave ablation instrument for cardiac applications, however, it should be appreciated that the described small diameter microwave ablation instrument could be used for a wide variety of non-cardiac ablation applications as well. The size and pitch of the described antenna coils may be widely varied. It should also be appreciated that the longitudinally oriented antenna coil does not need to be strictly parallel relative to the shaft axis and indeed, in some embodiments it may be desirable to tilt the antenna coil somewhat. This is especially true when the malleable shaft is reconfigured to the particular needs of the surgical application.

It should also be appreciated that the microwave antenna need not be helical in design. The concepts of the present invention may be applied to any kind of radiative structure, such as a monopole antenna, a printed antenna, a slow wave antenna, a lossy transmission antenna or the like. Furthermore, it should be appreciated that the transmission line does not absolutely have to be a coaxial cable. For example, the transmission line may be provided by a stripline, a microstrip line, a coplanar line, or the like.

Citations de brevets
Brevet cité Date de dépôt Date de publication Déposant Titre
US15866456 juil. 19251 juin 1926William BiermanMethod of and means for treating animal tissue to coagulate the same
US359810828 févr. 196910 août 1971Windschitl Harold EBiopsy technique and biopsy device
US382743610 nov. 19726 août 1974Frigitronics Of Conn IncMultipurpose cryosurgical probe
US38316077 mars 197327 août 1974Lindemann HElectrocoagulation grasping forceps for tube sterilization by means of bipolar high frequency heat radiation
US388694419 nov. 19733 juin 1975Jamshidi KhosrowMicrocautery device
US397608224 févr. 197524 août 1976German SchmittIntracardial stimulation electrode
US401187228 mars 197515 mars 1977Olympus Optical Co., Ltd.Electrical apparatus for treating affected part in a coeloma
US403335717 févr. 19765 juil. 1977Medtronic, Inc.Non-fibrosing cardiac electrode
US404505614 oct. 197530 août 1977Gennady Petrovich KandakovExpansion compensator for pipelines
US40732875 avr. 197614 févr. 1978American Medical Systems, Inc.Urethral profilometry catheter
US420454912 déc. 197727 mai 1980Rca CorporationCoaxial applicator for microwave hyperthermia
US424437120 mars 197913 janv. 1981Erbe Elektromedizin Gmbh & Co. KgHigh-frequency surgical apparatus
US426893724 mai 197926 mai 1981The English Card Clothing Company LimitedMetallic wire type card-clothing
US43123645 avr. 197826 janv. 1982C.G.R. MevApparatus for localized heating of a living tissue, using electromagnetic waves of ultra high frequency, for medical applications
US440999315 juil. 198118 oct. 1983Olympus Optical Co., Ltd.Endoscope apparatus
US441627626 oct. 198122 nov. 1983Valleylab, Inc.Adaptive, return electrode monitoring system
US44458926 mai 19821 mai 1984Laserscope, Inc.Dual balloon catheter device
US444819824 sept. 198115 mai 1984Bsd Medical CorporationInvasive hyperthermia apparatus and method
US44624122 avr. 198031 juil. 1984Bsd Medical CorporationFor causing heating in biological tissue specimens
US446507913 oct. 198214 août 1984Medtronic, Inc.Biomedical lead with fibrosis-inducing anchoring strand
US447687212 mai 198216 oct. 1984The Kendall CompanyEsophageal probe with disposable cover
US44945394 mai 198222 janv. 1985Toshio ZenitaniMethod and apparatus for surgical operation using microwaves
US452221214 nov. 198311 juin 1985Mansfield Scientific, Inc.Endocardial electrode
US456420014 déc. 198414 janv. 1986Loring Wolson JTethered ring game with hook configuration
US45652004 mai 198221 janv. 1986Cosman Eric RUniversal lesion and recording electrode system
US457347313 avr. 19844 mars 1986Cordis CorporationCardiac mapping probe
US458355613 déc. 198222 avr. 1986M/A-Com, Inc.For use in medical treatment of living tissue
US46012967 oct. 198322 juil. 1986Yeda Research And Development Co., Ltd.Hyperthermia apparatus
US461160411 janv. 198416 sept. 1986Siemens AktiengesellschaftBipolar electrode for medical applications
US46409838 avr. 19853 févr. 1987Institut Straumann AgConductor device, particularly for at least partial insertion in a human or animal body, comprising a spiral formed from at least one conductor
US46416465 avr. 198510 févr. 1987Kenneth E. SchultzEndotracheal tube/respirator tubing connecting lock mechanism and method of using same
US464164930 oct. 198510 févr. 1987Rca CorporationMethod and apparatus for high frequency catheter ablation
US464318630 oct. 198517 févr. 1987Rca CorporationPercutaneous transluminal microwave catheter angioplasty
US465521924 juin 19867 avr. 1987American Hospital Supply CorporationMulticomponent flexible grasping device
US465701514 févr. 198514 avr. 1987Werner IrnichControl device for a high frequency surgical apparatus
US466057118 juil. 198528 avr. 1987Cordis CorporationPercutaneous lead having radially adjustable electrode
US468112223 sept. 198521 juil. 1987Victory Engineering Corp.Stereotaxic catheter for microwave thermotherapy
US46854596 mars 198611 août 1987Fischer Met GmbhDevice for bipolar high-frequency coagulation of biological tissue
US469914725 sept. 198513 oct. 1987Cordis CorporationIntraventricular multielectrode cardial mapping probe and method for using same
US470071627 févr. 198620 oct. 1987Kasevich Associates, Inc.Collinear antenna array applicator
US476366828 oct. 198516 août 1988Mill Rose LaboratoriesPartible forceps instrument for endoscopy
US478581523 oct. 198522 nov. 1988Cordis CorporationApparatus for locating and ablating cardiac conduction pathways
US480089929 oct. 198631 janv. 1989Microthermia Technology, Inc.Apparatus for destroying cells in tumors and the like
US4823812 *5 mai 198725 avr. 1989Biodan Medical Systems Ltd.Applicator for insertion into a body opening for medical purposes
US482588019 juin 19872 mai 1989The Regents Of The University Of CaliforniaImplantable helical coil microwave antenna
US483204829 oct. 198723 mai 1989Cordis CorporationSuction ablation catheter
US484198815 oct. 198727 juin 1989Marquette Electronics, Inc.Microwave hyperthermia probe
US484199025 juin 198627 juin 1989Tokyo Keiki Co., Ltd.Applicator for use in hyperthermia
US488154328 juin 198821 nov. 1989Massachusetts Institute Of TechnologyCombined microwave heating and surface cooling of the cornea
US489148325 juin 19862 janv. 1990Tokyo Keiki Co. Ltd.Heating apparatus for hyperthermia
US492097831 août 19881 mai 1990Triangle Research And Development CorporationMethod and apparatus for the endoscopic treatment of deep tumors using RF hyperthermia
US49248634 mai 198815 mai 1990Mmtc, Inc.Angioplastic method for removing plaque from a vas
US492486427 avr. 198715 mai 1990Danzig Fred GApparatus and article for ligating blood vessels, nerves and other anatomical structures
US49324207 oct. 198812 juin 1990Clini-Therm CorporationNon-invasive quarter wavelength microwave applicator for hyperthermia treatment
US493821721 juin 19883 juil. 1990Massachusetts Institute Of TechnologyElectronically-controlled variable focus ultrasound hyperthermia system
US494591225 nov. 19887 août 1990Sensor Electronics, Inc.Catheter with radiofrequency heating applicator
US496013418 nov. 19882 oct. 1990Webster Wilton W JrSteerable catheter
US49665974 nov. 198830 oct. 1990Cosman Eric RThermometric cardiac tissue ablation electrode with ultra-sensitive temperature detection
US497671113 avr. 198911 déc. 1990Everest Medical CorporationAblation catheter with selectively deployable electrodes
US500743719 avr. 199016 avr. 1991Mmtc, Inc.Catheters for treating prostate disease
US50190767 déc. 198928 mai 1991Yamanashi William SRadio frequency surgical tool and method
US50443758 déc. 19893 sept. 1991Cardiac Pacemakers, Inc.Unitary intravascular defibrillating catheter with separate bipolar sensing
US50571069 juil. 199015 oct. 1991Kasevich Associates, Inc.Microwave balloon angioplasty
US507871330 nov. 19897 janv. 1992Spembly Medical LimitedCryosurgical probe
US508010119 juin 198914 janv. 1992Edap International, S.A.Method for examining and aiming treatment with untrasound
US508010221 avr. 198914 janv. 1992Edap International, S.A.Examining, localizing and treatment with ultrasound
US508565921 nov. 19904 févr. 1992Everest Medical CorporationBiopsy device with bipolar coagulation capability
US509784529 juin 199024 mars 1992Labthermics TechnologiesMicrowave hyperthermia probe
US510038825 mai 199031 mars 1992Interventional Thermodynamics, Inc.Method and device for thermal ablation of hollow body organs
US51043932 nov. 199014 avr. 1992Angelase, Inc.Catheter
US510839014 nov. 198828 avr. 1992Frigitronics, Inc.Flexible cryoprobe
US511182216 mai 198912 mai 1992Edap International, S.A.Piezoelectric article
US511440315 sept. 198919 mai 1992Eclipse Surgical Technologies, Inc.Catheter torque mechanism
US512939618 sept. 199014 juil. 1992Arye RosenMicrowave aided balloon angioplasty with lumen measurement
US513949620 déc. 199018 août 1992Hed Aharon ZUltrasonic freeze ablation catheters and probes
US514735523 sept. 198815 sept. 1992Brigham And Womens HospitalCryoablation catheter and method of performing cryoablation
US514735718 mars 199115 sept. 1992Rose Anthony TMedical instrument
US515071718 sept. 199029 sept. 1992Arye RosenMicrowave aided balloon angioplasty with guide filament
US515615115 févr. 199120 oct. 1992Cardiac Pathways CorporationEndocardial mapping and ablation system and catheter probe
US515809227 oct. 198827 oct. 1992Christian GlaceMethod and azimuthal probe for localizing the emergence point of ventricular tachycardias
US517125511 oct. 199115 déc. 1992Everest Medical CorporationBiopsy device
US517269919 oct. 199022 déc. 1992Angelase, Inc.Process of identification of a ventricular tachycardia (VT) active site and an ablation catheter system
US518812220 juin 199023 févr. 1993Rocket Of London LimitedMethod of causing endometrial destruction
US519005426 juil. 19912 mars 1993Labthermics Technologies, Inc.Microwave hyperthermia probe
US519227813 juin 19909 mars 1993Massachusetts Institute Of TechnologyMulti-fiber plug for a laser catheter
US520767214 janv. 19914 mai 1993Intra-Sonix, Inc.Instrument and method for intraluminally relieving stenosis
US520767413 mai 19914 mai 1993Hamilton Archie CFor treating tissue
US522250131 janv. 199229 juin 1993Duke UniversityMethods for the diagnosis and ablation treatment of ventricular tachycardia
US523033422 janv. 199227 juil. 1993Summit Technology, Inc.Method and apparatus for generating localized hyperthermia
US52303494 juin 199227 juil. 1993Sensor Electronics, Inc.Electrical heating catheter
US524244124 févr. 19927 sept. 1993Boaz AvitallDeflectable catheter with rotatable tip electrode
US52464389 janv. 199221 sept. 1993Sensor Electronics, Inc.Method of radiofrequency ablation
US52483121 juin 199228 sept. 1993Sensor Electronics, Inc.Liquid metal-filled balloon
US52634937 juil. 199223 nov. 1993Boaz AvitallDeflectable loop electrode array mapping and ablation catheter for cardiac chambers
US528121316 avr. 199225 janv. 1994Implemed, Inc.Catheter for ice mapping and ablation
US528121515 juin 199225 janv. 1994Implemed, Inc.Cryogenic catheter
US528121713 avr. 199225 janv. 1994Ep Technologies, Inc.Steerable antenna systems for cardiac ablation that minimize tissue damage and blood coagulation due to conductive heating patterns
US529386925 sept. 199215 mars 1994Ep Technologies, Inc.Cardiac probe with dynamic support for maintaining constant surface contact during heart systole and diastole
US529548419 mai 199222 mars 1994Arizona Board Of Regents For And On Behalf Of The University Of ArizonaApparatus and method for intra-cardiac ablation of arrhythmias
US5295955 *14 févr. 199222 mars 1994Amt, Inc.Method and apparatus for microwave aided liposuction
US5531677 *11 avr. 19952 juil. 1996Vidamed, Inc.Steerable medical probe with stylets
US5810803 *16 oct. 199622 sept. 1998Fidus Medical Technology CorporationConformal positioning assembly for microwave ablation catheter
US6068628 *20 août 199630 mai 2000Oratec Interventions, Inc.Apparatus for treating chondromalacia
US6514246 *7 juil. 19984 févr. 2003Ep Technologies, Inc.Systems and methods for forming large lesions in body tissue using curvilinear electrode elements
US20030014046 *27 févr. 200216 janv. 2003Conway-Stuart Medical, Inc.Sphincter treatment device
USRE3359022 nov. 198821 mai 1991Edap International, S.A.Method for examining, localizing and treating with ultrasound
Citations hors brevets
Référence
1"Biopsy Needles Liver, Kidney and Soft Tissue Biopsy Menghini Technique Aspirating Needle Set," Popper & Sons, Inc., Biomedical Instrument Division.
2Andriole et al., "Biopsy Needle Characteristics Assessed in the Laboratory," Radiology, vol. 148, No. 3, Sep. 1983, pp. 659-662.
3Arendt-Nielsen et al., "Selectively of Spatial Filters for Surface EMG Detection from the Tibialis Anterior Muscle," [online](C)200 [retrieved Nov. 23, 2003], 2 pages, Retrieved from the Internet: <URL:http://www.lisin.polito.it/english/annual reports/ar2002_uk/19uk.htm.
4Cheng, "Field and Wave Electromagnetics," 1989, Addison Wesley Publishing Co., Inc., pp. 485-509.
5Cox, "The Surgical Treatment of Atrial Fibrillation IV Surgical Technique," J. Thorac Cardiovasc. Surg. 101, 1991, pp. 584-592.
6Durney, et al., "Antennas for Medical Applications" Chapter 24, pp. 24-2, 24-27, 24-28, 24-29 and 24-58.
7Gottlieb, et al., "Interstitial Microwave Hyperthermia Applicators Having Submillimetre Diamters," Int. J. Hyperthermia, vol. 6, No. 3, 1990, pp. 707-714.
8Haines et al., "Tissue Heating During Radiofrequency Catheter Ablation: A Thermodynamic Model and Observation in Isolated Perfused and Superfused Canine Right Ventricular Free Wall," Pacint Clin Electrophysol, Jun. 1989, 12(6), pp. 962-976.
9James L. Cox "The Surgical Treatment of Atrial Fibrillation" Thorac Cardiovasc Surg., 402-426, 569-583 (1991).
10James L. Cox "The Surgical Treatment of Atrial Fibrillation" Thorac Cardiovasc Surg., 584-592 (1991).
11Knaut et al., "Interoperative Microwave Ablation for Curative Treatment of Atrial Fibrillation in Open Heart Surgery -The MICRO STAF and MICRO-PASS Pilot Trial," Thorac. Cardiovasc. Surg. 47 (Supplement), 1999, pp. 379-384.
12LaBonte et al., "Monopole Antennas for Microwave Catheter Ablation," IEEE Transactions on Microwave Theory ahd Techniques, vol. 44, No. 10, Oct. 1996, pp. 1832-1840.
13Langberg, et al., "Catheter Ablation of the Atrioventricular Junction Using a Helical Microwave Antenna: A Novel Means of Coupling Energy to Endocardium," Pace, vol. 14, Dec. 1991, pp. 2105-2113.
14Liem, et al., "Microwave Linear Ablation of the Isthmus Between the Inferior Vena Cava and Tricuspid Annulus," Pace, vol. 21, Nov. 1998, pp. 2079-2086.
15Matsukawa et al., "Percutaneous Microwave Coagulation Therapy in Liver Tumors: A 3-Year Experience," Acta Radioloigca, vol. 38, 1997, pp. 410-415.
16Murakami, et al., "Treatment of Hepatocellular Carcinoma: Value of Percutaneous Microwave Coagulation," American Journal of Roentgenology, vol. 164, No. 5, May 1995, pp. 1159-1164.
17Sato et al., "Microwave Coagulation Therapy for Hepatocellular Carcinoma," Gastroenterology, vol. 110, No. 5, May 1996, pp. 1507-1514.
18Sato et al., "Two Long-Term Survivors After Microwave Coagulation Therapy for Hepatocellular Carcinoma. A Case Report,", Hepatogastroenterology, vol. 43, No. 10, Jul. 1996, pp. 1035-1039.
19Seki et al., "Ultrasonically Guided Percutaneous Microwave Coagulation Therapy for Small Hepatocellular Carcinoma," Cancer, vol. 74, No. 3, Aug. 1, 1994, pp. 817-825.
20Thermodynamic Model and Observation in Isolated Perfused and Superfused Canine Right Ventricular Free Wall, Pacint Clin Electrophysol, Jun. 1989, 12(6), pp. 962-976.
Référencé par
Brevet citant Date de dépôt Date de publication Déposant Titre
US741048730 mars 200512 août 2008Ncontact Surgical, Inc.Vacuum coagulation probe for atrial fibrillation treatment
US757225718 août 200511 août 2009Ncontact Surgical, Inc.Vacuum coagulation and dissection probes
US775857812 mai 200620 juil. 2010Ncontact Surgical, Inc.Methods of coagulating tissue
US778066112 mai 200624 août 2010nContact Surgical, IncVacuum coagulation probes
US780315523 mai 200628 sept. 2010Ncontact Surgical, Inc.Vacuum coagulation probes
US803405316 juin 200911 oct. 2011Ncontact Surgical, Inc.Vacuum coagulation and dissection probes
US807153428 janv. 20096 déc. 2011Clean Technology International CorporationMaterial for facilitating thermal treatments of biological tissues and method of energy targeting leading to thermal treatment of biological tissues
US823599019 avr. 20077 août 2012Ncontact Surgical, Inc.Vacuum coagulation probes
US82990145 déc. 201130 oct. 2012Clean Technology International CorporationMaterial for facilitating thermal treatments of biological tissues and method of energy targeting leading to thermal treatment of biological tissues
US84545983 févr. 20124 juin 2013Ncontact Surgical, Inc.Vacuum coagulation probes
US851232813 oct. 200820 août 2013Covidien LpAntenna assemblies for medical applications
US861715326 févr. 201031 déc. 2013Covidien LpTunable microwave ablation probe
US874089330 juin 20103 juin 2014Covidien LpAdjustable tuning of a dielectrically loaded loop antenna
Classifications
Classification aux États-Unis606/49, 607/101
Classification internationaleA61B18/14, A61B18/18
Classification coopérativeA61B18/18, A61B18/14, A61B18/1815, A61B2018/00363, A61B2018/00291, A61B18/1402, A61B2018/00351, A61B2018/00577, A61B2018/1437
Classification européenneA61B18/18M, A61B18/14, A61B18/18, A61B18/14B
Événements juridiques
DateCodeÉvénementDescription
23 nov. 2010FPExpired due to failure to pay maintenance fee
Effective date: 20101003
3 oct. 2010LAPSLapse for failure to pay maintenance fees
10 mai 2010REMIMaintenance fee reminder mailed
25 févr. 2008ASAssignment
Owner name: MAQUET CARDIOVASCULAR LLC, CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BOSTON SCIENTIFIC LIMITED;BOSTON SCIENTIFIC SCIMED, INC.;CORVITA CORPORATION;AND OTHERS;REEL/FRAME:020550/0905
Effective date: 20080102
13 févr. 2007CCCertificate of correction
23 sept. 2002ASAssignment
Owner name: GUIDANT INVESTMENT CORPORATION, CALIFORNIA
Free format text: SECURITY AGREEMENT;ASSIGNOR:AFX INC.;REEL/FRAME:013309/0517
Effective date: 20020807